Effect of alcohol on the corrosion of al alloys in 1 N H2SO 4 solution Part i

The aim of this paper is to examine the effects of alcohol (1-buten–3-ol-l, 2-methyl–3-butyn–2-ol, 3-methyl–2-buten–1-ol, 3-methyl–3-buten–1-ol, 3-methyl–1-pentyn–3-ol, 5-hexen–1-ol) on the corrosion of Al alloys. The inhibiting effect of alcohol was investigated by electrochemical current-potential curves, atomic absorption spectrometry (AAS), metal microscopy,SEM and EDS. The results showed that alcohol (1-buten– 3-ol, 2-methyl–3-butyn–2-ol, 3-methyl–2-buten–1-ol, 3-methyl–3-buten–1-ol, 3-methyl–1-pentyn–3-ol, 5-hexen–1-ol) had an inhibiting effect on the corrosion of aluminium alloys. Experimental results show that corrosion of alloys in H 2 SO 4 solution have been effected by elements in alloys such as Cu, Zn, Mg and adsorption of alcohol on the surface of alloys in H 2 SO 4 solution obeys Temkin adsorption isotherm. The use of alcohol in H 2 SO 4 solution were shifted corrosion potentials (E cor ) to more negative values and acted as cathodic inhibitors on the aluminum alloys. EDS analysis of alloys displayed different intermetallic compounds on the surface of alloys, which might have changed the activity of alcohols depending on the surface morphology of alloys. This paper has showed that these alcohol inhibited corrosion of aluminium alloys in H 2 SO 4 solution. The concentration of 20 mM alcohol was shown that above 90% inhibition was achieved, which is a rather high value

Corrosion behaviour of coatings on 304 steel

The aim of this study is to determine the corrosion characteristics of 304 steel by the methods of Tafel extrapolation, linear polarization and electrochemical impedance spectroscopy (EIS). The steel surface is covered with nickel as electrochemical Watt's bath. Additionally, polyaniline (PANI) is synthesized on the steel electrode covered with nickel by the method of electrochemical cyclic voltammetry method. The effect of single and double coats of steel on corrosion resistance is examined in 3.5 % NaCl, 1N NaOH and 1N HCl solutions for the waiting time of 1, 48, 120 and 168 h. The surface morphology of steel, which is uncovered, is examined by SEM-EDX and the polyaniline is also examined in the same way. As well as the one covered with Ni + polyaniline is examined in the same way too. The synthesized polyaniline on the surface is analyzed by FTIR spectrum. Double coatings (Ni + polyaniline) has showed better corrosion resistance than single coating (polyaniline). Ni + polyaniline coatings in 1 N NaOH and 1 N HCl solutions has showed better corrosion resistance than polyaniline coating. The corrosion current of the steel covered with Ni + polyaniline in 1 N HCl and 1 N NaOH solutions is lower than the corrosion current of polyaniline coating. SEM-EDX analyses have showed that the surface covered with Ni + polyaniline is more homogenous and compact. This result is also convenient with the electrochemical experiment results

The effect of polypyrrole and nickel + polypyrrole coatings on corrosion behaviour AISI 304 stainless steel

Polypyrrole (PPy) and nickel + PPy (Ni + PPy) coatings have been occured on AISI 304 stainless steel (304 SS) surface by cyclic voltammetry technique in aqueous oxalic acid solutions and as the supporting electrolytes was used saccharin and NaNO3. Corrosion behavior of the PPy and Ni + PPy coated 304 SS elec trodes was investigated using linear anodic polarization, Tafel extrapolation and electrochemical impedance spectroscopy (EIS) techniques in various aqueous solutions. The polypyrrole coated samples were character ized by scanning electron microscope (SEM) and Fourier Transform Infrared spectroscopy (FTIR). SEM analysis showed that PPy structure depends closely on the electrochemical conditions. Additionally, it is seen from FTIR analysis, characteristic polypyrrole absorption bands have occurred in all the coated surfaces. Tafel analyses and open circuit potential datas revealed that the PPy and Ni + PPy coatings effectively pro tect the steel from corrosion in H2SO4 and NaOH solutions. However, the corrosion protection properties were reduced with immersion time. Ni + PPy coatings more effectively protects the steel from corrosion than polypyrrol

The effect of 3-Methyl 1-Pentyn 3-ol on the corrosion of Al-Si-Cu alloys in acid solutions by using SEM, EDX and AAS

In this study, the effect of alloying elements on the corrosion of Al-Si-Cu alloys in H 2 SO 4 and HCl media content 3-methyl–1pentyn–3-ol (3mlp3ol) is investigated by using SEM, EDX, AAS. The effect of active elements and 3-methyl–1-pentyn–3-ol (inhibitor) on the corrosion of alloys is determined using SEM, EDX and AAS results. Experimental results which indicated active alloying elements are Cu, Zn, Mg for Al-Si-Cu alloys in the studied solutions

Polarized Neutron Reflectometry of Nickel Corrosion Inhibitors.

Polarized neutron reflectometry has been used to investigate the detailed adsorption behavior and corrosion inhibition mechanism of two surfactants on a nickel surface under acidic conditions. Both the corrosion of the nickel surface and the structure of the adsorbed surfactant layer could be monitored in situ by the use of different solvent contrasts. Layer thicknesses and roughnesses were evaluated over a range of pH values, showing distinctly the superior corrosion inhibition of one negatively charged surfactant (sodium dodecyl sulfate) compared to a positively charged example (dodecyl trimethylammonium bromide) due to its stronger binding interaction with the surface. It was found that adequate corrosion inhibition occurs at significantly less than full surface coverage.X-ray photoelectron spectra were obtained at the National Engineering and Physical Sciences Research Council (EPSRC) XPS User’s Service (NEXUS) at Newcastle University, an EPSRC midrange facility. NR data were obtained on the D17 instrument, and samples were treated in the laboratories of the Partnership for Soft Condensed Matter (PSCM) at the Institut Laue-Langevin. M.H.W. is grateful for funding from the Oppenheimer Trust.This is the final version of the article. It first appeared from the American Chemical Society via http://dx.doi.org/10.1021/acs.langmuir.5b0171

Effects of alcohols on the corrosion of aluminum alloys in 1 N HCl solution. Part II

The use of alcohols as cathodic inhibitors in HCl solution results in a negative shift of corrosion potential (Ecor). The alcohols concentration of 20 mM, was shown to be the best one. EDX analyses of the alloys showed different intermetallics at the surface of alloys, which made the activity of alcohols in the studied solutions change depending on the surface morphology of the alloys. Experiments indicated that the alcohols adsorption of the alloys in HCl solution obeys Temkin adsorption isotherm rule. The corrosion of the alloys in the solutions was affected by alloying with Cu, Zn, and Mg. For a comparison, pure forms of Al, Cu, Zn, Mg were tested in the solutions

Methanol oxidation on Aluminium-Copper-Silicon alloys coated with polyprrole

Methanol oxidation on the aluminum copper silicon alloys which are coated with polyprrole were investigated in 1 N H2SO4 by using electrochemical method. For this purpose, first the current density potential curve of alloys were obtained in 1 N H2SO4 + x M pyrrole solutions, determined passive zones are coated with polyprrole alloys in H2SO4 solutions. Then the current potential curves were obtained in 1 N H2SO4 + x M methanol with aluminum alloys and these are expected at +1.5 V against to the standard calomel electrode (SCE) at the different times in 1 N H2SO4 + 10–3 M pyrrole that were obtained with dif ferent scan rates. The extreme methanol oxidation was seen on the E110 and E140 alloys which are coated with polyprrole. Embedded pH electrode solutions which were coated with polypyrrole in 1 N H2SO4 and 1 N H2SO4 + 0.5 M methanol solutions were measured after 30 minutes at +2.1 V